How penetrated is U.S. club membership?

Bernstein Research indicates the U.S. warehouse club market is highly saturated, with 80% penetration among higher-income households, significantly limiting domestic growth for companies like Costco. This saturation underscores the critical importance of international expansion for Costco, where its overseas warehouses serve three times more members per store than in North America, to sustain membership fee revenue, which accounts for over half of its operating income. Bernstein projects Costco's fee income growth could slow to 5-6% if U.S./Canada-centric, versus a potential 7% CAGR if international markets drive new store openings, despite Costco's continued domestic market share gains.

Analysis

According to Bernstein Research, the U.S. warehouse club market has reached a high level of saturation, with an estimated penetration of 80% among households earning over $50,000 annually. This environment significantly constrains domestic growth prospects for key players, including Costco. Despite this, Costco has demonstrated superior competitive positioning by increasing its market penetration within this demographic from 22% to 37% over the past decade, capturing share from rivals like Sam's Club and BJ's. The critical growth vector for Costco is now international expansion, where its warehouses exhibit significantly higher member density, averaging approximately 350,000 members per store compared to 115,000 in the U.S. and Canada. This international potential is crucial as membership fees, which generate $5.1 billion annually, account for over half of the company's operating income. Bernstein projects that fee income growth could achieve a 7% compound annual rate if international markets constitute over 75% of new store openings by fiscal 2030, but this rate could decelerate to the 5-6% range if expansion remains concentrated in North America.

Key Decisions for Investors

• Investors should closely monitor the geographic mix of Costco's new store openings, as the company's future earnings growth is heavily dependent on successful international expansion to offset domestic market saturation.
• Given that membership fees contribute to over half of operating income, any adjustments to renewal rates, new member growth, or the timing of a future fee increase are critical variables that will directly impact profitability.
• Consider Costco's demonstrated ability to gain market share in a mature U.S. market as a key defensive attribute, justifying a potential premium relative to peers like WMT (Sam's Club) and BJ, who face the same saturation headwinds with less momentum.
• Evaluate valuation multiples for COST in the context of its shifting growth profile, weighing the high-potential international story against the projected moderation of overall membership fee growth to a 5-7% CAGR.